1. Field of the Invention
This invention relates to a packaging material for photosensitive materials such as photographic photosensitive materials.
2. Description of the Prior Art
As to the materials which are adversely affected by exposure to light, such as photographic photosensitive materials, packaging materials capable of blocking light completely are used. The packaging materials must have sufficient physical strength such as breaking strength, tear strength, impact puncture strength according to the volume and weight of a photosensitive material and heat sealing properties as well as the above light-shielding ability. Moreover, the packaging material must have antistatic ability to prevent static problems.
As conventional packaging materials having antistatic ability, there were a packaging material composed of an aluminum foil on both sides of which a polyolefin resin light-shielding film and a bleached kraft paper were laminated with an adhesive and a packaging material composed of an aluminum metallized film instead of the aluminum foil (Japanese Patent KOKAI No. 63-30482 and No. 63-247033). Another packaging material was composed of a layer containing an antistatic agent instead of the aluminum metallized film or the like.
However, in the case of the above packaging material containing an antistatic agent, the antistatic agent bleeds from the material over time so as to leave less than the amount necessary to prevent static problems. Therefore, it is inferior in heat sealability, appearance and touch and in the case that the packaging material is used for a photographic photosensitive material, the antistatic agent which bleeds from the packaging material adheres to the emulsion layer of the photographic photosensitive material to induce development problems.